Related Parties - Logistics Leasing, LLC (Details) - Equity Method Investee	Jun. 30, 2019	Dec. 31, 2018	Jul. 26, 2017	Sep. 21, 2015
Related Party Transaction [Line Items]
Ownership interest acquired			50.00%
Equity method investment, ownership percentage	47.60%	47.60%	51.00%	33.30%

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant